git.sesse.net Git - bcachefs-tools-debian/blob - libbcachefs/io.c

   1 /*
   2  * Some low level IO code, and hacks for various block layer limitations
   3  *
   4  * Copyright 2010, 2011 Kent Overstreet <kent.overstreet@gmail.com>
   5  * Copyright 2012 Google, Inc.
   6  */
   7
   8 #include "bcachefs.h"
   9 #include "alloc_foreground.h"
  10 #include "bset.h"
  11 #include "btree_update.h"
  12 #include "buckets.h"
  13 #include "checksum.h"
  14 #include "compress.h"
  15 #include "clock.h"
  16 #include "debug.h"
  17 #include "disk_groups.h"
  18 #include "ec.h"
  19 #include "error.h"
  20 #include "extents.h"
  21 #include "io.h"
  22 #include "journal.h"
  23 #include "keylist.h"
  24 #include "move.h"
  25 #include "rebalance.h"
  26 #include "super.h"
  27 #include "super-io.h"
  28
  29 #include <linux/blkdev.h>
  30 #include <linux/random.h>
  31
  32 #include <trace/events/bcachefs.h>
  33
  34 static bool bch2_target_congested(struct bch_fs *c, u16 target)
  35 {
  36         const struct bch_devs_mask *devs;
  37         unsigned d, nr = 0, total = 0;
  38         u64 now = local_clock(), last;
  39         s64 congested;
  40         struct bch_dev *ca;
  41
  42         if (!target)
  43                 return false;
  44
  45         rcu_read_lock();
  46         devs = bch2_target_to_mask(c, target);
  47         for_each_set_bit(d, devs->d, BCH_SB_MEMBERS_MAX) {
  48                 ca = rcu_dereference(c->devs[d]);
  49                 if (!ca)
  50                         continue;
  51
  52                 congested = atomic_read(&ca->congested);
  53                 last = READ_ONCE(ca->congested_last);
  54                 if (time_after64(now, last))
  55                         congested -= (now - last) >> 12;
  56
  57                 total += max(congested, 0LL);
  58                 nr++;
  59         }
  60         rcu_read_unlock();
  61
  62         return bch2_rand_range(nr * CONGESTED_MAX) < total;
  63 }
  64
  65 static inline void bch2_congested_acct(struct bch_dev *ca, u64 io_latency,
  66                                        u64 now, int rw)
  67 {
  68         u64 latency_capable =
  69                 ca->io_latency[rw].quantiles.entries[QUANTILE_IDX(1)].m;
  70         /* ideally we'd be taking into account the device's variance here: */
  71         u64 latency_threshold = latency_capable << (rw == READ ? 2 : 3);
  72         s64 latency_over = io_latency - latency_threshold;
  73
  74         if (latency_threshold && latency_over > 0) {
  75                 /*
  76                  * bump up congested by approximately latency_over * 4 /
  77                  * latency_threshold - we don't need much accuracy here so don't
  78                  * bother with the divide:
  79                  */
  80                 if (atomic_read(&ca->congested) < CONGESTED_MAX)
  81                         atomic_add(latency_over >>
  82                                    max_t(int, ilog2(latency_threshold) - 2, 0),
  83                                    &ca->congested);
  84
  85                 ca->congested_last = now;
  86         } else if (atomic_read(&ca->congested) > 0) {
  87                 atomic_dec(&ca->congested);
  88         }
  89 }
  90
  91 void bch2_latency_acct(struct bch_dev *ca, u64 submit_time, int rw)
  92 {
  93         atomic64_t *latency = &ca->cur_latency[rw];
  94         u64 now = local_clock();
  95         u64 io_latency = time_after64(now, submit_time)
  96                 ? now - submit_time
  97                 : 0;
  98         u64 old, new, v = atomic64_read(latency);
  99
 100         do {
 101                 old = v;
 102
 103                 /*
 104                  * If the io latency was reasonably close to the current
 105                  * latency, skip doing the update and atomic operation - most of
 106                  * the time:
 107                  */
 108                 if (abs((int) (old - io_latency)) < (old >> 1) &&
 109                     now & ~(~0 << 5))
 110                         break;
 111
 112                 new = ewma_add(old, io_latency, 5);
 113         } while ((v = atomic64_cmpxchg(latency, old, new)) != old);
 114
 115         bch2_congested_acct(ca, io_latency, now, rw);
 116
 117         __bch2_time_stats_update(&ca->io_latency[rw], submit_time, now);
 118 }
 119
 120 /* Allocate, free from mempool: */
 121
 122 void bch2_bio_free_pages_pool(struct bch_fs *c, struct bio *bio)
 123 {
 124         struct bio_vec *bv;
 125         unsigned i;
 126
 127         bio_for_each_segment_all(bv, bio, i)
 128                 if (bv->bv_page != ZERO_PAGE(0))
 129                         mempool_free(bv->bv_page, &c->bio_bounce_pages);
 130         bio->bi_vcnt = 0;
 131 }
 132
 133 static void bch2_bio_alloc_page_pool(struct bch_fs *c, struct bio *bio,
 134                                     bool *using_mempool)
 135 {
 136         struct bio_vec *bv = &bio->bi_io_vec[bio->bi_vcnt++];
 137
 138         if (likely(!*using_mempool)) {
 139                 bv->bv_page = alloc_page(GFP_NOIO);
 140                 if (unlikely(!bv->bv_page)) {
 141                         mutex_lock(&c->bio_bounce_pages_lock);
 142                         *using_mempool = true;
 143                         goto pool_alloc;
 144
 145                 }
 146         } else {
 147 pool_alloc:
 148                 bv->bv_page = mempool_alloc(&c->bio_bounce_pages, GFP_NOIO);
 149         }
 150
 151         bv->bv_len = PAGE_SIZE;
 152         bv->bv_offset = 0;
 153 }
 154
 155 void bch2_bio_alloc_pages_pool(struct bch_fs *c, struct bio *bio,
 156                                size_t bytes)
 157 {
 158         bool using_mempool = false;
 159
 160         BUG_ON(DIV_ROUND_UP(bytes, PAGE_SIZE) > bio->bi_max_vecs);
 161
 162         bio->bi_iter.bi_size = bytes;
 163
 164         while (bio->bi_vcnt < DIV_ROUND_UP(bytes, PAGE_SIZE))
 165                 bch2_bio_alloc_page_pool(c, bio, &using_mempool);
 166
 167         if (using_mempool)
 168                 mutex_unlock(&c->bio_bounce_pages_lock);
 169 }
 170
 171 void bch2_bio_alloc_more_pages_pool(struct bch_fs *c, struct bio *bio,
 172                                     size_t bytes)
 173 {
 174         while (bio->bi_vcnt < DIV_ROUND_UP(bytes, PAGE_SIZE)) {
 175                 struct bio_vec *bv = &bio->bi_io_vec[bio->bi_vcnt];
 176
 177                 BUG_ON(bio->bi_vcnt >= bio->bi_max_vecs);
 178
 179                 bv->bv_page = alloc_page(GFP_NOIO);
 180                 if (!bv->bv_page) {
 181                         /*
 182                          * We already allocated from mempool, we can't allocate from it again
 183                          * without freeing the pages we already allocated or else we could
 184                          * deadlock:
 185                          */
 186                         bch2_bio_free_pages_pool(c, bio);
 187                         bch2_bio_alloc_pages_pool(c, bio, bytes);
 188                         return;
 189                 }
 190
 191                 bv->bv_len = PAGE_SIZE;
 192                 bv->bv_offset = 0;
 193                 bio->bi_vcnt++;
 194         }
 195
 196         bio->bi_iter.bi_size = bytes;
 197 }
 198
 199 /* Writes */
 200
 201 void bch2_submit_wbio_replicas(struct bch_write_bio *wbio, struct bch_fs *c,
 202                                enum bch_data_type type,
 203                                const struct bkey_i *k)
 204 {
 205         struct bkey_ptrs_c ptrs = bch2_bkey_ptrs_c(bkey_i_to_s_c(k));
 206         const struct bch_extent_ptr *ptr;
 207         struct bch_write_bio *n;
 208         struct bch_dev *ca;
 209
 210         BUG_ON(c->opts.nochanges);
 211
 212         bkey_for_each_ptr(ptrs, ptr) {
 213                 BUG_ON(ptr->dev >= BCH_SB_MEMBERS_MAX ||
 214                        !c->devs[ptr->dev]);
 215
 216                 ca = bch_dev_bkey_exists(c, ptr->dev);
 217
 218                 if (to_entry(ptr + 1) < ptrs.end) {
 219                         n = to_wbio(bio_clone_fast(&wbio->bio, GFP_NOIO,
 220                                                    &ca->replica_set));
 221
 222                         n->bio.bi_end_io        = wbio->bio.bi_end_io;
 223                         n->bio.bi_private       = wbio->bio.bi_private;
 224                         n->parent               = wbio;
 225                         n->split                = true;
 226                         n->bounce               = false;
 227                         n->put_bio              = true;
 228                         n->bio.bi_opf           = wbio->bio.bi_opf;
 229                         bio_inc_remaining(&wbio->bio);
 230                 } else {
 231                         n = wbio;
 232                         n->split                = false;
 233                 }
 234
 235                 n->c                    = c;
 236                 n->dev                  = ptr->dev;
 237                 n->have_ioref           = bch2_dev_get_ioref(ca, WRITE);
 238                 n->submit_time          = local_clock();
 239                 n->bio.bi_iter.bi_sector = ptr->offset;
 240
 241                 if (!journal_flushes_device(ca))
 242                         n->bio.bi_opf |= REQ_FUA;
 243
 244                 if (likely(n->have_ioref)) {
 245                         this_cpu_add(ca->io_done->sectors[WRITE][type],
 246                                      bio_sectors(&n->bio));
 247
 248                         bio_set_dev(&n->bio, ca->disk_sb.bdev);
 249                         submit_bio(&n->bio);
 250                 } else {
 251                         n->bio.bi_status        = BLK_STS_REMOVED;
 252                         bio_endio(&n->bio);
 253                 }
 254         }
 255 }
 256
 257 static void __bch2_write(struct closure *);
 258
 259 static void bch2_write_done(struct closure *cl)
 260 {
 261         struct bch_write_op *op = container_of(cl, struct bch_write_op, cl);
 262         struct bch_fs *c = op->c;
 263
 264         if (!op->error && (op->flags & BCH_WRITE_FLUSH))
 265                 op->error = bch2_journal_error(&c->journal);
 266
 267         if (!(op->flags & BCH_WRITE_NOPUT_RESERVATION))
 268                 bch2_disk_reservation_put(c, &op->res);
 269         percpu_ref_put(&c->writes);
 270         bch2_keylist_free(&op->insert_keys, op->inline_keys);
 271
 272         bch2_time_stats_update(&c->times[BCH_TIME_data_write], op->start_time);
 273
 274         closure_return(cl);
 275 }
 276
 277 int bch2_write_index_default(struct bch_write_op *op)
 278 {
 279         struct bch_fs *c = op->c;
 280         struct btree_trans trans;
 281         struct btree_iter *iter;
 282         struct keylist *keys = &op->insert_keys;
 283         int ret;
 284
 285         BUG_ON(bch2_keylist_empty(keys));
 286         bch2_verify_keylist_sorted(keys);
 287
 288         bch2_trans_init(&trans, c);
 289
 290         iter = bch2_trans_get_iter(&trans, BTREE_ID_EXTENTS,
 291                                    bkey_start_pos(&bch2_keylist_front(keys)->k),
 292                                    BTREE_ITER_INTENT);
 293
 294         do {
 295                 BKEY_PADDED(k) split;
 296
 297                 bkey_copy(&split.k, bch2_keylist_front(keys));
 298
 299                 bch2_extent_trim_atomic(&split.k, iter);
 300
 301                 bch2_trans_update(&trans,
 302                                   BTREE_INSERT_ENTRY(iter, &split.k));
 303
 304                 ret = bch2_trans_commit(&trans, &op->res, op_journal_seq(op),
 305                                         BTREE_INSERT_NOFAIL|
 306                                         BTREE_INSERT_USE_RESERVE);
 307                 if (ret)
 308                         break;
 309
 310                 if (bkey_cmp(iter->pos, bch2_keylist_front(keys)->k.p) < 0)
 311                         bch2_cut_front(iter->pos, bch2_keylist_front(keys));
 312                 else
 313                         bch2_keylist_pop_front(keys);
 314         } while (!bch2_keylist_empty(keys));
 315
 316         bch2_trans_exit(&trans);
 317
 318         return ret;
 319 }
 320
 321 /**
 322  * bch_write_index - after a write, update index to point to new data
 323  */
 324 static void __bch2_write_index(struct bch_write_op *op)
 325 {
 326         struct bch_fs *c = op->c;
 327         struct keylist *keys = &op->insert_keys;
 328         struct bch_extent_ptr *ptr;
 329         struct bkey_i *src, *dst = keys->keys, *n, *k;
 330         unsigned dev;
 331         int ret;
 332
 333         for (src = keys->keys; src != keys->top; src = n) {
 334                 n = bkey_next(src);
 335                 bkey_copy(dst, src);
 336
 337                 bch2_bkey_drop_ptrs(bkey_i_to_s(dst), ptr,
 338                         test_bit(ptr->dev, op->failed.d));
 339
 340                 if (!bch2_bkey_nr_ptrs(bkey_i_to_s_c(dst))) {
 341                         ret = -EIO;
 342                         goto err;
 343                 }
 344
 345                 dst = bkey_next(dst);
 346         }
 347
 348         keys->top = dst;
 349
 350         /*
 351          * probably not the ideal place to hook this in, but I don't
 352          * particularly want to plumb io_opts all the way through the btree
 353          * update stack right now
 354          */
 355         for_each_keylist_key(keys, k)
 356                 bch2_rebalance_add_key(c, bkey_i_to_s_c(k), &op->opts);
 357
 358         if (!bch2_keylist_empty(keys)) {
 359                 u64 sectors_start = keylist_sectors(keys);
 360                 int ret = op->index_update_fn(op);
 361
 362                 BUG_ON(keylist_sectors(keys) && !ret);
 363
 364                 op->written += sectors_start - keylist_sectors(keys);
 365
 366                 if (ret) {
 367                         __bcache_io_error(c, "btree IO error %i", ret);
 368                         op->error = ret;
 369                 }
 370         }
 371 out:
 372         /* If some a bucket wasn't written, we can't erasure code it: */
 373         for_each_set_bit(dev, op->failed.d, BCH_SB_MEMBERS_MAX)
 374                 bch2_open_bucket_write_error(c, &op->open_buckets, dev);
 375
 376         bch2_open_buckets_put(c, &op->open_buckets);
 377         return;
 378 err:
 379         keys->top = keys->keys;
 380         op->error = ret;
 381         goto out;
 382 }
 383
 384 static void bch2_write_index(struct closure *cl)
 385 {
 386         struct bch_write_op *op = container_of(cl, struct bch_write_op, cl);
 387         struct bch_fs *c = op->c;
 388
 389         __bch2_write_index(op);
 390
 391         if (!op->error && (op->flags & BCH_WRITE_FLUSH)) {
 392                 bch2_journal_flush_seq_async(&c->journal,
 393                                              *op_journal_seq(op),
 394                                              cl);
 395                 continue_at(cl, bch2_write_done, index_update_wq(op));
 396         } else {
 397                 continue_at_nobarrier(cl, bch2_write_done, NULL);
 398         }
 399 }
 400
 401 static void bch2_write_endio(struct bio *bio)
 402 {
 403         struct closure *cl              = bio->bi_private;
 404         struct bch_write_op *op         = container_of(cl, struct bch_write_op, cl);
 405         struct bch_write_bio *wbio      = to_wbio(bio);
 406         struct bch_write_bio *parent    = wbio->split ? wbio->parent : NULL;
 407         struct bch_fs *c                = wbio->c;
 408         struct bch_dev *ca              = bch_dev_bkey_exists(c, wbio->dev);
 409
 410         if (bch2_dev_io_err_on(bio->bi_status, ca, "data write"))
 411                 set_bit(wbio->dev, op->failed.d);
 412
 413         if (wbio->have_ioref) {
 414                 bch2_latency_acct(ca, wbio->submit_time, WRITE);
 415                 percpu_ref_put(&ca->io_ref);
 416         }
 417
 418         if (wbio->bounce)
 419                 bch2_bio_free_pages_pool(c, bio);
 420
 421         if (wbio->put_bio)
 422                 bio_put(bio);
 423
 424         if (parent)
 425                 bio_endio(&parent->bio);
 426         else
 427                 closure_put(cl);
 428 }
 429
 430 static void init_append_extent(struct bch_write_op *op,
 431                                struct write_point *wp,
 432                                struct bversion version,
 433                                struct bch_extent_crc_unpacked crc)
 434 {
 435         struct bkey_i_extent *e = bkey_extent_init(op->insert_keys.top);
 436         struct bch_extent_ptr *ptr;
 437
 438         op->pos.offset += crc.uncompressed_size;
 439         e->k.p = op->pos;
 440         e->k.size = crc.uncompressed_size;
 441         e->k.version = version;
 442
 443         bch2_extent_crc_append(e, crc);
 444         bch2_alloc_sectors_append_ptrs(op->c, wp, &e->k_i,
 445                                        crc.compressed_size);
 446
 447         if (op->flags & BCH_WRITE_CACHED)
 448                 extent_for_each_ptr(extent_i_to_s(e), ptr)
 449                         ptr->cached = true;
 450
 451         bch2_keylist_push(&op->insert_keys);
 452 }
 453
 454 static struct bio *bch2_write_bio_alloc(struct bch_fs *c,
 455                                         struct write_point *wp,
 456                                         struct bio *src,
 457                                         bool *page_alloc_failed,
 458                                         void *buf)
 459 {
 460         struct bch_write_bio *wbio;
 461         struct bio *bio;
 462         unsigned output_available =
 463                 min(wp->sectors_free << 9, src->bi_iter.bi_size);
 464         unsigned pages = DIV_ROUND_UP(output_available, PAGE_SIZE);
 465
 466         bio = bio_alloc_bioset(GFP_NOIO, pages, &c->bio_write);
 467         wbio                    = wbio_init(bio);
 468         wbio->put_bio           = true;
 469         /* copy WRITE_SYNC flag */
 470         wbio->bio.bi_opf        = src->bi_opf;
 471
 472         if (buf) {
 473                 bio->bi_iter.bi_size = output_available;
 474                 bch2_bio_map(bio, buf);
 475                 return bio;
 476         }
 477
 478         wbio->bounce            = true;
 479
 480         /*
 481          * We can't use mempool for more than c->sb.encoded_extent_max
 482          * worth of pages, but we'd like to allocate more if we can:
 483          */
 484         while (bio->bi_iter.bi_size < output_available) {
 485                 unsigned len = min_t(unsigned, PAGE_SIZE,
 486                                      output_available - bio->bi_iter.bi_size);
 487                 struct page *p;
 488
 489                 p = alloc_page(GFP_NOIO);
 490                 if (!p) {
 491                         unsigned pool_max =
 492                                 min_t(unsigned, output_available,
 493                                       c->sb.encoded_extent_max << 9);
 494
 495                         if (bio_sectors(bio) < pool_max)
 496                                 bch2_bio_alloc_pages_pool(c, bio, pool_max);
 497                         break;
 498                 }
 499
 500                 bio->bi_io_vec[bio->bi_vcnt++] = (struct bio_vec) {
 501                         .bv_page        = p,
 502                         .bv_len         = len,
 503                         .bv_offset      = 0,
 504                 };
 505                 bio->bi_iter.bi_size += len;
 506         }
 507
 508         *page_alloc_failed = bio->bi_vcnt < pages;
 509         return bio;
 510 }
 511
 512 static int bch2_write_rechecksum(struct bch_fs *c,
 513                                  struct bch_write_op *op,
 514                                  unsigned new_csum_type)
 515 {
 516         struct bio *bio = &op->wbio.bio;
 517         struct bch_extent_crc_unpacked new_crc;
 518         int ret;
 519
 520         /* bch2_rechecksum_bio() can't encrypt or decrypt data: */
 521
 522         if (bch2_csum_type_is_encryption(op->crc.csum_type) !=
 523             bch2_csum_type_is_encryption(new_csum_type))
 524                 new_csum_type = op->crc.csum_type;
 525
 526         ret = bch2_rechecksum_bio(c, bio, op->version, op->crc,
 527                                   NULL, &new_crc,
 528                                   op->crc.offset, op->crc.live_size,
 529                                   new_csum_type);
 530         if (ret)
 531                 return ret;
 532
 533         bio_advance(bio, op->crc.offset << 9);
 534         bio->bi_iter.bi_size = op->crc.live_size << 9;
 535         op->crc = new_crc;
 536         return 0;
 537 }
 538
 539 static int bch2_write_decrypt(struct bch_write_op *op)
 540 {
 541         struct bch_fs *c = op->c;
 542         struct nonce nonce = extent_nonce(op->version, op->crc);
 543         struct bch_csum csum;
 544
 545         if (!bch2_csum_type_is_encryption(op->crc.csum_type))
 546                 return 0;
 547
 548         /*
 549          * If we need to decrypt data in the write path, we'll no longer be able
 550          * to verify the existing checksum (poly1305 mac, in this case) after
 551          * it's decrypted - this is the last point we'll be able to reverify the
 552          * checksum:
 553          */
 554         csum = bch2_checksum_bio(c, op->crc.csum_type, nonce, &op->wbio.bio);
 555         if (bch2_crc_cmp(op->crc.csum, csum))
 556                 return -EIO;
 557
 558         bch2_encrypt_bio(c, op->crc.csum_type, nonce, &op->wbio.bio);
 559         op->crc.csum_type = 0;
 560         op->crc.csum = (struct bch_csum) { 0, 0 };
 561         return 0;
 562 }
 563
 564 static enum prep_encoded_ret {
 565         PREP_ENCODED_OK,
 566         PREP_ENCODED_ERR,
 567         PREP_ENCODED_CHECKSUM_ERR,
 568         PREP_ENCODED_DO_WRITE,
 569 } bch2_write_prep_encoded_data(struct bch_write_op *op, struct write_point *wp)
 570 {
 571         struct bch_fs *c = op->c;
 572         struct bio *bio = &op->wbio.bio;
 573
 574         if (!(op->flags & BCH_WRITE_DATA_ENCODED))
 575                 return PREP_ENCODED_OK;
 576
 577         BUG_ON(bio_sectors(bio) != op->crc.compressed_size);
 578
 579         /* Can we just write the entire extent as is? */
 580         if (op->crc.uncompressed_size == op->crc.live_size &&
 581             op->crc.compressed_size <= wp->sectors_free &&
 582             op->crc.compression_type == op->compression_type) {
 583                 if (!op->crc.compression_type &&
 584                     op->csum_type != op->crc.csum_type &&
 585                     bch2_write_rechecksum(c, op, op->csum_type))
 586                         return PREP_ENCODED_CHECKSUM_ERR;
 587
 588                 return PREP_ENCODED_DO_WRITE;
 589         }
 590
 591         /*
 592          * If the data is compressed and we couldn't write the entire extent as
 593          * is, we have to decompress it:
 594          */
 595         if (op->crc.compression_type) {
 596                 struct bch_csum csum;
 597
 598                 if (bch2_write_decrypt(op))
 599                         return PREP_ENCODED_CHECKSUM_ERR;
 600
 601                 /* Last point we can still verify checksum: */
 602                 csum = bch2_checksum_bio(c, op->crc.csum_type,
 603                                          extent_nonce(op->version, op->crc),
 604                                          bio);
 605                 if (bch2_crc_cmp(op->crc.csum, csum))
 606                         return PREP_ENCODED_CHECKSUM_ERR;
 607
 608                 if (bch2_bio_uncompress_inplace(c, bio, &op->crc))
 609                         return PREP_ENCODED_ERR;
 610         }
 611
 612         /*
 613          * No longer have compressed data after this point - data might be
 614          * encrypted:
 615          */
 616
 617         /*
 618          * If the data is checksummed and we're only writing a subset,
 619          * rechecksum and adjust bio to point to currently live data:
 620          */
 621         if ((op->crc.live_size != op->crc.uncompressed_size ||
 622              op->crc.csum_type != op->csum_type) &&
 623             bch2_write_rechecksum(c, op, op->csum_type))
 624                 return PREP_ENCODED_CHECKSUM_ERR;
 625
 626         /*
 627          * If we want to compress the data, it has to be decrypted:
 628          */
 629         if ((op->compression_type ||
 630              bch2_csum_type_is_encryption(op->crc.csum_type) !=
 631              bch2_csum_type_is_encryption(op->csum_type)) &&
 632             bch2_write_decrypt(op))
 633                 return PREP_ENCODED_CHECKSUM_ERR;
 634
 635         return PREP_ENCODED_OK;
 636 }
 637
 638 static int bch2_write_extent(struct bch_write_op *op, struct write_point *wp)
 639 {
 640         struct bch_fs *c = op->c;
 641         struct bio *src = &op->wbio.bio, *dst = src;
 642         struct bvec_iter saved_iter;
 643         struct bkey_i *key_to_write;
 644         void *ec_buf;
 645         unsigned key_to_write_offset = op->insert_keys.top_p -
 646                 op->insert_keys.keys_p;
 647         unsigned total_output = 0, total_input = 0;
 648         bool bounce = false;
 649         bool page_alloc_failed = false;
 650         int ret, more = 0;
 651
 652         BUG_ON(!bio_sectors(src));
 653
 654         ec_buf = bch2_writepoint_ec_buf(c, wp);
 655
 656         switch (bch2_write_prep_encoded_data(op, wp)) {
 657         case PREP_ENCODED_OK:
 658                 break;
 659         case PREP_ENCODED_ERR:
 660                 ret = -EIO;
 661                 goto err;
 662         case PREP_ENCODED_CHECKSUM_ERR:
 663                 goto csum_err;
 664         case PREP_ENCODED_DO_WRITE:
 665                 if (ec_buf) {
 666                         dst = bch2_write_bio_alloc(c, wp, src,
 667                                                    &page_alloc_failed,
 668                                                    ec_buf);
 669                         bio_copy_data(dst, src);
 670                         bounce = true;
 671                 }
 672                 init_append_extent(op, wp, op->version, op->crc);
 673                 goto do_write;
 674         }
 675
 676         if (ec_buf ||
 677             op->compression_type ||
 678             (op->csum_type &&
 679              !(op->flags & BCH_WRITE_PAGES_STABLE)) ||
 680             (bch2_csum_type_is_encryption(op->csum_type) &&
 681              !(op->flags & BCH_WRITE_PAGES_OWNED))) {
 682                 dst = bch2_write_bio_alloc(c, wp, src,
 683                                            &page_alloc_failed,
 684                                            ec_buf);
 685                 bounce = true;
 686         }
 687
 688         saved_iter = dst->bi_iter;
 689
 690         do {
 691                 struct bch_extent_crc_unpacked crc =
 692                         (struct bch_extent_crc_unpacked) { 0 };
 693                 struct bversion version = op->version;
 694                 size_t dst_len, src_len;
 695
 696                 if (page_alloc_failed &&
 697                     bio_sectors(dst) < wp->sectors_free &&
 698                     bio_sectors(dst) < c->sb.encoded_extent_max)
 699                         break;
 700
 701                 BUG_ON(op->compression_type &&
 702                        (op->flags & BCH_WRITE_DATA_ENCODED) &&
 703                        bch2_csum_type_is_encryption(op->crc.csum_type));
 704                 BUG_ON(op->compression_type && !bounce);
 705
 706                 crc.compression_type = op->compression_type
 707                         ?  bch2_bio_compress(c, dst, &dst_len, src, &src_len,
 708                                              op->compression_type)
 709                         : 0;
 710                 if (!crc.compression_type) {
 711                         dst_len = min(dst->bi_iter.bi_size, src->bi_iter.bi_size);
 712                         dst_len = min_t(unsigned, dst_len, wp->sectors_free << 9);
 713
 714                         if (op->csum_type)
 715                                 dst_len = min_t(unsigned, dst_len,
 716                                                 c->sb.encoded_extent_max << 9);
 717
 718                         if (bounce) {
 719                                 swap(dst->bi_iter.bi_size, dst_len);
 720                                 bio_copy_data(dst, src);
 721                                 swap(dst->bi_iter.bi_size, dst_len);
 722                         }
 723
 724                         src_len = dst_len;
 725                 }
 726
 727                 BUG_ON(!src_len || !dst_len);
 728
 729                 if (bch2_csum_type_is_encryption(op->csum_type)) {
 730                         if (bversion_zero(version)) {
 731                                 version.lo = atomic64_inc_return(&c->key_version) + 1;
 732                         } else {
 733                                 crc.nonce = op->nonce;
 734                                 op->nonce += src_len >> 9;
 735                         }
 736                 }
 737
 738                 if ((op->flags & BCH_WRITE_DATA_ENCODED) &&
 739                     !crc.compression_type &&
 740                     bch2_csum_type_is_encryption(op->crc.csum_type) ==
 741                     bch2_csum_type_is_encryption(op->csum_type)) {
 742                         /*
 743                          * Note: when we're using rechecksum(), we need to be
 744                          * checksumming @src because it has all the data our
 745                          * existing checksum covers - if we bounced (because we
 746                          * were trying to compress), @dst will only have the
 747                          * part of the data the new checksum will cover.
 748                          *
 749                          * But normally we want to be checksumming post bounce,
 750                          * because part of the reason for bouncing is so the
 751                          * data can't be modified (by userspace) while it's in
 752                          * flight.
 753                          */
 754                         if (bch2_rechecksum_bio(c, src, version, op->crc,
 755                                         &crc, &op->crc,
 756                                         src_len >> 9,
 757                                         bio_sectors(src) - (src_len >> 9),
 758                                         op->csum_type))
 759                                 goto csum_err;
 760                 } else {
 761                         if ((op->flags & BCH_WRITE_DATA_ENCODED) &&
 762                             bch2_rechecksum_bio(c, src, version, op->crc,
 763                                         NULL, &op->crc,
 764                                         src_len >> 9,
 765                                         bio_sectors(src) - (src_len >> 9),
 766                                         op->crc.csum_type))
 767                                 goto csum_err;
 768
 769                         crc.compressed_size     = dst_len >> 9;
 770                         crc.uncompressed_size   = src_len >> 9;
 771                         crc.live_size           = src_len >> 9;
 772
 773                         swap(dst->bi_iter.bi_size, dst_len);
 774                         bch2_encrypt_bio(c, op->csum_type,
 775                                          extent_nonce(version, crc), dst);
 776                         crc.csum = bch2_checksum_bio(c, op->csum_type,
 777                                          extent_nonce(version, crc), dst);
 778                         crc.csum_type = op->csum_type;
 779                         swap(dst->bi_iter.bi_size, dst_len);
 780                 }
 781
 782                 init_append_extent(op, wp, version, crc);
 783
 784                 if (dst != src)
 785                         bio_advance(dst, dst_len);
 786                 bio_advance(src, src_len);
 787                 total_output    += dst_len;
 788                 total_input     += src_len;
 789         } while (dst->bi_iter.bi_size &&
 790                  src->bi_iter.bi_size &&
 791                  wp->sectors_free &&
 792                  !bch2_keylist_realloc(&op->insert_keys,
 793                                       op->inline_keys,
 794                                       ARRAY_SIZE(op->inline_keys),
 795                                       BKEY_EXTENT_U64s_MAX));
 796
 797         more = src->bi_iter.bi_size != 0;
 798
 799         dst->bi_iter = saved_iter;
 800
 801         if (dst == src && more) {
 802                 BUG_ON(total_output != total_input);
 803
 804                 dst = bio_split(src, total_input >> 9,
 805                                 GFP_NOIO, &c->bio_write);
 806                 wbio_init(dst)->put_bio = true;
 807                 /* copy WRITE_SYNC flag */
 808                 dst->bi_opf             = src->bi_opf;
 809         }
 810
 811         dst->bi_iter.bi_size = total_output;
 812
 813         /* Free unneeded pages after compressing: */
 814         if (to_wbio(dst)->bounce)
 815                 while (dst->bi_vcnt > DIV_ROUND_UP(dst->bi_iter.bi_size, PAGE_SIZE))
 816                         mempool_free(dst->bi_io_vec[--dst->bi_vcnt].bv_page,
 817                                      &c->bio_bounce_pages);
 818 do_write:
 819         /* might have done a realloc... */
 820
 821         key_to_write = (void *) (op->insert_keys.keys_p + key_to_write_offset);
 822
 823         bch2_ec_add_backpointer(c, wp,
 824                                 bkey_start_pos(&key_to_write->k),
 825                                 total_input >> 9);
 826
 827         dst->bi_end_io  = bch2_write_endio;
 828         dst->bi_private = &op->cl;
 829         bio_set_op_attrs(dst, REQ_OP_WRITE, 0);
 830
 831         closure_get(dst->bi_private);
 832
 833         bch2_submit_wbio_replicas(to_wbio(dst), c, BCH_DATA_USER,
 834                                   key_to_write);
 835         return more;
 836 csum_err:
 837         bch_err(c, "error verifying existing checksum while "
 838                 "rewriting existing data (memory corruption?)");
 839         ret = -EIO;
 840 err:
 841         if (to_wbio(dst)->bounce)
 842                 bch2_bio_free_pages_pool(c, dst);
 843         if (to_wbio(dst)->put_bio)
 844                 bio_put(dst);
 845
 846         return ret;
 847 }
 848
 849 static void __bch2_write(struct closure *cl)
 850 {
 851         struct bch_write_op *op = container_of(cl, struct bch_write_op, cl);
 852         struct bch_fs *c = op->c;
 853         struct write_point *wp;
 854         int ret;
 855 again:
 856         memset(&op->failed, 0, sizeof(op->failed));
 857
 858         do {
 859                 /* +1 for possible cache device: */
 860                 if (op->open_buckets.nr + op->nr_replicas + 1 >
 861                     ARRAY_SIZE(op->open_buckets.v))
 862                         goto flush_io;
 863
 864                 if (bch2_keylist_realloc(&op->insert_keys,
 865                                         op->inline_keys,
 866                                         ARRAY_SIZE(op->inline_keys),
 867                                         BKEY_EXTENT_U64s_MAX))
 868                         goto flush_io;
 869
 870                 wp = bch2_alloc_sectors_start(c,
 871                         op->target,
 872                         op->opts.erasure_code,
 873                         op->write_point,
 874                         &op->devs_have,
 875                         op->nr_replicas,
 876                         op->nr_replicas_required,
 877                         op->alloc_reserve,
 878                         op->flags,
 879                         (op->flags & BCH_WRITE_ALLOC_NOWAIT) ? NULL : cl);
 880                 EBUG_ON(!wp);
 881
 882                 if (unlikely(IS_ERR(wp))) {
 883                         if (unlikely(PTR_ERR(wp) != -EAGAIN)) {
 884                                 ret = PTR_ERR(wp);
 885                                 goto err;
 886                         }
 887
 888                         goto flush_io;
 889                 }
 890
 891                 ret = bch2_write_extent(op, wp);
 892
 893                 bch2_open_bucket_get(c, wp, &op->open_buckets);
 894                 bch2_alloc_sectors_done(c, wp);
 895
 896                 if (ret < 0)
 897                         goto err;
 898         } while (ret);
 899
 900         continue_at(cl, bch2_write_index, index_update_wq(op));
 901         return;
 902 err:
 903         op->error = ret;
 904
 905         continue_at(cl, !bch2_keylist_empty(&op->insert_keys)
 906                     ? bch2_write_index
 907                     : bch2_write_done, index_update_wq(op));
 908         return;
 909 flush_io:
 910         closure_sync(cl);
 911
 912         if (!bch2_keylist_empty(&op->insert_keys)) {
 913                 __bch2_write_index(op);
 914
 915                 if (op->error) {
 916                         continue_at_nobarrier(cl, bch2_write_done, NULL);
 917                         return;
 918                 }
 919         }
 920
 921         goto again;
 922 }
 923
 924 /**
 925  * bch_write - handle a write to a cache device or flash only volume
 926  *
 927  * This is the starting point for any data to end up in a cache device; it could
 928  * be from a normal write, or a writeback write, or a write to a flash only
 929  * volume - it's also used by the moving garbage collector to compact data in
 930  * mostly empty buckets.
 931  *
 932  * It first writes the data to the cache, creating a list of keys to be inserted
 933  * (if the data won't fit in a single open bucket, there will be multiple keys);
 934  * after the data is written it calls bch_journal, and after the keys have been
 935  * added to the next journal write they're inserted into the btree.
 936  *
 937  * If op->discard is true, instead of inserting the data it invalidates the
 938  * region of the cache represented by op->bio and op->inode.
 939  */
 940 void bch2_write(struct closure *cl)
 941 {
 942         struct bch_write_op *op = container_of(cl, struct bch_write_op, cl);
 943         struct bch_fs *c = op->c;
 944
 945         BUG_ON(!op->nr_replicas);
 946         BUG_ON(!op->write_point.v);
 947         BUG_ON(!bkey_cmp(op->pos, POS_MAX));
 948         BUG_ON(bio_sectors(&op->wbio.bio) > U16_MAX);
 949
 950         op->start_time = local_clock();
 951
 952         bch2_keylist_init(&op->insert_keys, op->inline_keys);
 953         wbio_init(&op->wbio.bio)->put_bio = false;
 954
 955         if (c->opts.nochanges ||
 956             !percpu_ref_tryget(&c->writes)) {
 957                 __bcache_io_error(c, "read only");
 958                 op->error = -EROFS;
 959                 if (!(op->flags & BCH_WRITE_NOPUT_RESERVATION))
 960                         bch2_disk_reservation_put(c, &op->res);
 961                 closure_return(cl);
 962                 return;
 963         }
 964
 965         bch2_increment_clock(c, bio_sectors(&op->wbio.bio), WRITE);
 966
 967         continue_at_nobarrier(cl, __bch2_write, NULL);
 968 }
 969
 970 /* Cache promotion on read */
 971
 972 struct promote_op {
 973         struct closure          cl;
 974         struct rcu_head         rcu;
 975         u64                     start_time;
 976
 977         struct rhash_head       hash;
 978         struct bpos             pos;
 979
 980         struct migrate_write    write;
 981         struct bio_vec          bi_inline_vecs[0]; /* must be last */
 982 };
 983
 984 static const struct rhashtable_params bch_promote_params = {
 985         .head_offset    = offsetof(struct promote_op, hash),
 986         .key_offset     = offsetof(struct promote_op, pos),
 987         .key_len        = sizeof(struct bpos),
 988 };
 989
 990 static inline bool should_promote(struct bch_fs *c, struct bkey_s_c k,
 991                                   struct bpos pos,
 992                                   struct bch_io_opts opts,
 993                                   unsigned flags)
 994 {
 995         if (!opts.promote_target)
 996                 return false;
 997
 998         if (!(flags & BCH_READ_MAY_PROMOTE))
 999                 return false;
1000
1001         if (percpu_ref_is_dying(&c->writes))
1002                 return false;
1003
1004         if (!bkey_extent_is_data(k.k))
1005                 return false;
1006
1007         if (bch2_extent_has_target(c, bkey_s_c_to_extent(k), opts.promote_target))
1008                 return false;
1009
1010         if (bch2_target_congested(c, opts.promote_target))
1011                 return false;
1012
1013         if (rhashtable_lookup_fast(&c->promote_table, &pos,
1014                                    bch_promote_params))
1015                 return false;
1016
1017         return true;
1018 }
1019
1020 static void promote_free(struct bch_fs *c, struct promote_op *op)
1021 {
1022         int ret;
1023
1024         ret = rhashtable_remove_fast(&c->promote_table, &op->hash,
1025                                      bch_promote_params);
1026         BUG_ON(ret);
1027         percpu_ref_put(&c->writes);
1028         kfree_rcu(op, rcu);
1029 }
1030
1031 static void promote_done(struct closure *cl)
1032 {
1033         struct promote_op *op =
1034                 container_of(cl, struct promote_op, cl);
1035         struct bch_fs *c = op->write.op.c;
1036
1037         bch2_time_stats_update(&c->times[BCH_TIME_data_promote],
1038                                op->start_time);
1039
1040         bch2_bio_free_pages_pool(c, &op->write.op.wbio.bio);
1041         promote_free(c, op);
1042 }
1043
1044 static void promote_start(struct promote_op *op, struct bch_read_bio *rbio)
1045 {
1046         struct bch_fs *c = rbio->c;
1047         struct closure *cl = &op->cl;
1048         struct bio *bio = &op->write.op.wbio.bio;
1049
1050         trace_promote(&rbio->bio);
1051
1052         /* we now own pages: */
1053         BUG_ON(!rbio->bounce);
1054         BUG_ON(rbio->bio.bi_vcnt > bio->bi_max_vecs);
1055
1056         memcpy(bio->bi_io_vec, rbio->bio.bi_io_vec,
1057                sizeof(struct bio_vec) * rbio->bio.bi_vcnt);
1058         swap(bio->bi_vcnt, rbio->bio.bi_vcnt);
1059
1060         bch2_migrate_read_done(&op->write, rbio);
1061
1062         closure_init(cl, NULL);
1063         closure_call(&op->write.op.cl, bch2_write, c->wq, cl);
1064         closure_return_with_destructor(cl, promote_done);
1065 }
1066
1067 noinline
1068 static struct promote_op *__promote_alloc(struct bch_fs *c,
1069                                           struct bpos pos,
1070                                           struct extent_ptr_decoded *pick,
1071                                           struct bch_io_opts opts,
1072                                           unsigned rbio_sectors,
1073                                           struct bch_read_bio **rbio)
1074 {
1075         struct promote_op *op = NULL;
1076         struct bio *bio;
1077         unsigned rbio_pages = DIV_ROUND_UP(rbio_sectors, PAGE_SECTORS);
1078         /* data might have to be decompressed in the write path: */
1079         unsigned wbio_pages = DIV_ROUND_UP(pick->crc.uncompressed_size,
1080                                            PAGE_SECTORS);
1081         int ret;
1082
1083         if (!percpu_ref_tryget(&c->writes))
1084                 return NULL;
1085
1086         op = kzalloc(sizeof(*op) + sizeof(struct bio_vec) * wbio_pages,
1087                      GFP_NOIO);
1088         if (!op)
1089                 goto err;
1090
1091         op->start_time = local_clock();
1092         op->pos = pos;
1093
1094         /*
1095          * promotes require bouncing, but if the extent isn't
1096          * checksummed/compressed it might be too big for the mempool:
1097          */
1098         if (rbio_sectors > c->sb.encoded_extent_max) {
1099                 *rbio = kzalloc(sizeof(struct bch_read_bio) +
1100                                 sizeof(struct bio_vec) * rbio_pages,
1101                                 GFP_NOIO);
1102                 if (!*rbio)
1103                         goto err;
1104
1105                 rbio_init(&(*rbio)->bio, opts);
1106                 bio_init(&(*rbio)->bio, (*rbio)->bio.bi_inline_vecs,
1107                          rbio_pages);
1108
1109                 (*rbio)->bio.bi_iter.bi_size = rbio_sectors << 9;
1110                 bch2_bio_map(&(*rbio)->bio, NULL);
1111
1112                 if (bch2_bio_alloc_pages(&(*rbio)->bio, GFP_NOIO))
1113                         goto err;
1114
1115                 (*rbio)->bounce         = true;
1116                 (*rbio)->split          = true;
1117                 (*rbio)->kmalloc        = true;
1118         }
1119
1120         if (rhashtable_lookup_insert_fast(&c->promote_table, &op->hash,
1121                                           bch_promote_params))
1122                 goto err;
1123
1124         bio = &op->write.op.wbio.bio;
1125         bio_init(bio, bio->bi_inline_vecs, wbio_pages);
1126
1127         ret = bch2_migrate_write_init(c, &op->write,
1128                         writepoint_hashed((unsigned long) current),
1129                         opts,
1130                         DATA_PROMOTE,
1131                         (struct data_opts) {
1132                                 .target = opts.promote_target
1133                         },
1134                         bkey_s_c_null);
1135         BUG_ON(ret);
1136
1137         return op;
1138 err:
1139         if (*rbio)
1140                 bio_free_pages(&(*rbio)->bio);
1141         kfree(*rbio);
1142         *rbio = NULL;
1143         kfree(op);
1144         percpu_ref_put(&c->writes);
1145         return NULL;
1146 }
1147
1148 static inline struct promote_op *promote_alloc(struct bch_fs *c,
1149                                                struct bvec_iter iter,
1150                                                struct bkey_s_c k,
1151                                                struct extent_ptr_decoded *pick,
1152                                                struct bch_io_opts opts,
1153                                                unsigned flags,
1154                                                struct bch_read_bio **rbio,
1155                                                bool *bounce,
1156                                                bool *read_full)
1157 {
1158         bool promote_full = *read_full || READ_ONCE(c->promote_whole_extents);
1159         unsigned sectors = promote_full
1160                 ? pick->crc.compressed_size
1161                 : bvec_iter_sectors(iter);
1162         struct bpos pos = promote_full
1163                 ? bkey_start_pos(k.k)
1164                 : POS(k.k->p.inode, iter.bi_sector);
1165         struct promote_op *promote;
1166
1167         if (!should_promote(c, k, pos, opts, flags))
1168                 return NULL;
1169
1170         promote = __promote_alloc(c, pos, pick, opts, sectors, rbio);
1171         if (!promote)
1172                 return NULL;
1173
1174         *bounce         = true;
1175         *read_full      = promote_full;
1176         return promote;
1177 }
1178
1179 /* Read */
1180
1181 #define READ_RETRY_AVOID        1
1182 #define READ_RETRY              2
1183 #define READ_ERR                3
1184
1185 enum rbio_context {
1186         RBIO_CONTEXT_NULL,
1187         RBIO_CONTEXT_HIGHPRI,
1188         RBIO_CONTEXT_UNBOUND,
1189 };
1190
1191 static inline struct bch_read_bio *
1192 bch2_rbio_parent(struct bch_read_bio *rbio)
1193 {
1194         return rbio->split ? rbio->parent : rbio;
1195 }
1196
1197 __always_inline
1198 static void bch2_rbio_punt(struct bch_read_bio *rbio, work_func_t fn,
1199                            enum rbio_context context,
1200                            struct workqueue_struct *wq)
1201 {
1202         if (context <= rbio->context) {
1203                 fn(&rbio->work);
1204         } else {
1205                 rbio->work.func         = fn;
1206                 rbio->context           = context;
1207                 queue_work(wq, &rbio->work);
1208         }
1209 }
1210
1211 static inline struct bch_read_bio *bch2_rbio_free(struct bch_read_bio *rbio)
1212 {
1213         BUG_ON(rbio->bounce && !rbio->split);
1214
1215         if (rbio->promote)
1216                 promote_free(rbio->c, rbio->promote);
1217         rbio->promote = NULL;
1218
1219         if (rbio->bounce)
1220                 bch2_bio_free_pages_pool(rbio->c, &rbio->bio);
1221
1222         if (rbio->split) {
1223                 struct bch_read_bio *parent = rbio->parent;
1224
1225                 if (rbio->kmalloc)
1226                         kfree(rbio);
1227                 else
1228                         bio_put(&rbio->bio);
1229
1230                 rbio = parent;
1231         }
1232
1233         return rbio;
1234 }
1235
1236 static void bch2_rbio_done(struct bch_read_bio *rbio)
1237 {
1238         bch2_time_stats_update(&rbio->c->times[BCH_TIME_data_read],
1239                                rbio->start_time);
1240         bio_endio(&rbio->bio);
1241 }
1242
1243 static void bch2_read_retry_nodecode(struct bch_fs *c, struct bch_read_bio *rbio,
1244                                      struct bvec_iter bvec_iter, u64 inode,
1245                                      struct bch_io_failures *failed,
1246                                      unsigned flags)
1247 {
1248         struct btree_iter iter;
1249         BKEY_PADDED(k) tmp;
1250         struct bkey_s_c k;
1251         int ret;
1252
1253         flags &= ~BCH_READ_LAST_FRAGMENT;
1254
1255         bch2_btree_iter_init(&iter, c, BTREE_ID_EXTENTS,
1256                              rbio->pos, BTREE_ITER_SLOTS);
1257 retry:
1258         rbio->bio.bi_status = 0;
1259
1260         k = bch2_btree_iter_peek_slot(&iter);
1261         if (btree_iter_err(k)) {
1262                 bch2_btree_iter_unlock(&iter);
1263                 goto err;
1264         }
1265
1266         bkey_reassemble(&tmp.k, k);
1267         k = bkey_i_to_s_c(&tmp.k);
1268         bch2_btree_iter_unlock(&iter);
1269
1270         if (!bkey_extent_is_data(k.k) ||
1271             !bch2_extent_matches_ptr(c, bkey_i_to_s_c_extent(&tmp.k),
1272                                      rbio->pick.ptr,
1273                                      rbio->pos.offset -
1274                                      rbio->pick.crc.offset)) {
1275                 /* extent we wanted to read no longer exists: */
1276                 rbio->hole = true;
1277                 goto out;
1278         }
1279
1280         ret = __bch2_read_extent(c, rbio, bvec_iter, k, failed, flags);
1281         if (ret == READ_RETRY)
1282                 goto retry;
1283         if (ret)
1284                 goto err;
1285         goto out;
1286 err:
1287         rbio->bio.bi_status = BLK_STS_IOERR;
1288 out:
1289         bch2_rbio_done(rbio);
1290 }
1291
1292 static void bch2_read_retry(struct bch_fs *c, struct bch_read_bio *rbio,
1293                             struct bvec_iter bvec_iter, u64 inode,
1294                             struct bch_io_failures *failed, unsigned flags)
1295 {
1296         struct btree_iter iter;
1297         struct bkey_s_c k;
1298         int ret;
1299
1300         flags &= ~BCH_READ_LAST_FRAGMENT;
1301         flags |= BCH_READ_MUST_CLONE;
1302 retry:
1303         for_each_btree_key(&iter, c, BTREE_ID_EXTENTS,
1304                            POS(inode, bvec_iter.bi_sector),
1305                            BTREE_ITER_SLOTS, k) {
1306                 BKEY_PADDED(k) tmp;
1307                 unsigned bytes;
1308
1309                 bkey_reassemble(&tmp.k, k);
1310                 k = bkey_i_to_s_c(&tmp.k);
1311                 bch2_btree_iter_unlock(&iter);
1312
1313                 bytes = min_t(unsigned, bvec_iter.bi_size,
1314                               (k.k->p.offset - bvec_iter.bi_sector) << 9);
1315                 swap(bvec_iter.bi_size, bytes);
1316
1317                 ret = __bch2_read_extent(c, rbio, bvec_iter, k, failed, flags);
1318                 switch (ret) {
1319                 case READ_RETRY:
1320                         goto retry;
1321                 case READ_ERR:
1322                         goto err;
1323                 };
1324
1325                 if (bytes == bvec_iter.bi_size)
1326                         goto out;
1327
1328                 swap(bvec_iter.bi_size, bytes);
1329                 bio_advance_iter(&rbio->bio, &bvec_iter, bytes);
1330         }
1331
1332         /*
1333          * If we get here, it better have been because there was an error
1334          * reading a btree node
1335          */
1336         ret = bch2_btree_iter_unlock(&iter);
1337         BUG_ON(!ret);
1338         __bcache_io_error(c, "btree IO error %i", ret);
1339 err:
1340         rbio->bio.bi_status = BLK_STS_IOERR;
1341 out:
1342         bch2_rbio_done(rbio);
1343 }
1344
1345 static void bch2_rbio_retry(struct work_struct *work)
1346 {
1347         struct bch_read_bio *rbio =
1348                 container_of(work, struct bch_read_bio, work);
1349         struct bch_fs *c        = rbio->c;
1350         struct bvec_iter iter   = rbio->bvec_iter;
1351         unsigned flags          = rbio->flags;
1352         u64 inode               = rbio->pos.inode;
1353         struct bch_io_failures failed = { .nr = 0 };
1354
1355         trace_read_retry(&rbio->bio);
1356
1357         if (rbio->retry == READ_RETRY_AVOID)
1358                 bch2_mark_io_failure(&failed, &rbio->pick);
1359
1360         rbio->bio.bi_status = 0;
1361
1362         rbio = bch2_rbio_free(rbio);
1363
1364         flags |= BCH_READ_IN_RETRY;
1365         flags &= ~BCH_READ_MAY_PROMOTE;
1366
1367         if (flags & BCH_READ_NODECODE)
1368                 bch2_read_retry_nodecode(c, rbio, iter, inode, &failed, flags);
1369         else
1370                 bch2_read_retry(c, rbio, iter, inode, &failed, flags);
1371 }
1372
1373 static void bch2_rbio_error(struct bch_read_bio *rbio, int retry,
1374                             blk_status_t error)
1375 {
1376         rbio->retry = retry;
1377
1378         if (rbio->flags & BCH_READ_IN_RETRY)
1379                 return;
1380
1381         if (retry == READ_ERR) {
1382                 rbio = bch2_rbio_free(rbio);
1383
1384                 rbio->bio.bi_status = error;
1385                 bch2_rbio_done(rbio);
1386         } else {
1387                 bch2_rbio_punt(rbio, bch2_rbio_retry,
1388                                RBIO_CONTEXT_UNBOUND, system_unbound_wq);
1389         }
1390 }
1391
1392 static void bch2_rbio_narrow_crcs(struct bch_read_bio *rbio)
1393 {
1394         struct bch_fs *c = rbio->c;
1395         struct btree_trans trans;
1396         struct btree_iter *iter;
1397         struct bkey_s_c k;
1398         struct bkey_i_extent *e;
1399         BKEY_PADDED(k) new;
1400         struct bch_extent_crc_unpacked new_crc;
1401         unsigned offset;
1402         int ret;
1403
1404         if (rbio->pick.crc.compression_type)
1405                 return;
1406
1407         bch2_trans_init(&trans, c);
1408 retry:
1409         bch2_trans_begin(&trans);
1410
1411         iter = bch2_trans_get_iter(&trans, BTREE_ID_EXTENTS, rbio->pos,
1412                                    BTREE_ITER_INTENT);
1413         k = bch2_btree_iter_peek(iter);
1414         if (IS_ERR_OR_NULL(k.k))
1415                 goto out;
1416
1417         if (!bkey_extent_is_data(k.k))
1418                 goto out;
1419
1420         bkey_reassemble(&new.k, k);
1421         e = bkey_i_to_extent(&new.k);
1422
1423         if (!bch2_extent_matches_ptr(c, extent_i_to_s_c(e),
1424                                      rbio->pick.ptr,
1425                                      rbio->pos.offset -
1426                                      rbio->pick.crc.offset) ||
1427             bversion_cmp(e->k.version, rbio->version))
1428                 goto out;
1429
1430         /* Extent was merged? */
1431         if (bkey_start_offset(&e->k) < rbio->pos.offset ||
1432             e->k.p.offset > rbio->pos.offset + rbio->pick.crc.uncompressed_size)
1433                 goto out;
1434
1435         /* The extent might have been partially overwritten since we read it: */
1436         offset = rbio->pick.crc.offset + (bkey_start_offset(&e->k) - rbio->pos.offset);
1437
1438         if (bch2_rechecksum_bio(c, &rbio->bio, rbio->version,
1439                                 rbio->pick.crc, NULL, &new_crc,
1440                                 offset, e->k.size,
1441                                 rbio->pick.crc.csum_type)) {
1442                 bch_err(c, "error verifying existing checksum while narrowing checksum (memory corruption?)");
1443                 goto out;
1444         }
1445
1446         if (!bch2_extent_narrow_crcs(e, new_crc))
1447                 goto out;
1448
1449         bch2_trans_update(&trans, BTREE_INSERT_ENTRY(iter, &e->k_i));
1450         ret = bch2_trans_commit(&trans, NULL, NULL,
1451                                 BTREE_INSERT_ATOMIC|
1452                                 BTREE_INSERT_NOFAIL|
1453                                 BTREE_INSERT_NOWAIT);
1454         if (ret == -EINTR)
1455                 goto retry;
1456 out:
1457         bch2_trans_exit(&trans);
1458 }
1459
1460 static bool should_narrow_crcs(struct bkey_s_c k,
1461                                struct extent_ptr_decoded *pick,
1462                                unsigned flags)
1463 {
1464         return !(flags & BCH_READ_IN_RETRY) &&
1465                 bkey_extent_is_data(k.k) &&
1466                 bch2_can_narrow_extent_crcs(bkey_s_c_to_extent(k), pick->crc);
1467 }
1468
1469 /* Inner part that may run in process context */
1470 static void __bch2_read_endio(struct work_struct *work)
1471 {
1472         struct bch_read_bio *rbio =
1473                 container_of(work, struct bch_read_bio, work);
1474         struct bch_fs *c        = rbio->c;
1475         struct bch_dev *ca      = bch_dev_bkey_exists(c, rbio->pick.ptr.dev);
1476         struct bio *src         = &rbio->bio;
1477         struct bio *dst         = &bch2_rbio_parent(rbio)->bio;
1478         struct bvec_iter dst_iter = rbio->bvec_iter;
1479         struct bch_extent_crc_unpacked crc = rbio->pick.crc;
1480         struct nonce nonce = extent_nonce(rbio->version, crc);
1481         struct bch_csum csum;
1482
1483         /* Reset iterator for checksumming and copying bounced data: */
1484         if (rbio->bounce) {
1485                 src->bi_iter.bi_size            = crc.compressed_size << 9;
1486                 src->bi_iter.bi_idx             = 0;
1487                 src->bi_iter.bi_bvec_done       = 0;
1488         } else {
1489                 src->bi_iter                    = rbio->bvec_iter;
1490         }
1491
1492         csum = bch2_checksum_bio(c, crc.csum_type, nonce, src);
1493         if (bch2_crc_cmp(csum, rbio->pick.crc.csum))
1494                 goto csum_err;
1495
1496         if (unlikely(rbio->narrow_crcs))
1497                 bch2_rbio_narrow_crcs(rbio);
1498
1499         if (rbio->flags & BCH_READ_NODECODE)
1500                 goto nodecode;
1501
1502         /* Adjust crc to point to subset of data we want: */
1503         crc.offset     += rbio->bvec_iter.bi_sector - rbio->pos.offset;
1504         crc.live_size   = bvec_iter_sectors(rbio->bvec_iter);
1505
1506         if (crc.compression_type != BCH_COMPRESSION_NONE) {
1507                 bch2_encrypt_bio(c, crc.csum_type, nonce, src);
1508                 if (bch2_bio_uncompress(c, src, dst, dst_iter, crc))
1509                         goto decompression_err;
1510         } else {
1511                 /* don't need to decrypt the entire bio: */
1512                 nonce = nonce_add(nonce, crc.offset << 9);
1513                 bio_advance(src, crc.offset << 9);
1514
1515                 BUG_ON(src->bi_iter.bi_size < dst_iter.bi_size);
1516                 src->bi_iter.bi_size = dst_iter.bi_size;
1517
1518                 bch2_encrypt_bio(c, crc.csum_type, nonce, src);
1519
1520                 if (rbio->bounce) {
1521                         struct bvec_iter src_iter = src->bi_iter;
1522                         bio_copy_data_iter(dst, &dst_iter, src, &src_iter);
1523                 }
1524         }
1525
1526         if (rbio->promote) {
1527                 /*
1528                  * Re encrypt data we decrypted, so it's consistent with
1529                  * rbio->crc:
1530                  */
1531                 bch2_encrypt_bio(c, crc.csum_type, nonce, src);
1532                 promote_start(rbio->promote, rbio);
1533                 rbio->promote = NULL;
1534         }
1535 nodecode:
1536         if (likely(!(rbio->flags & BCH_READ_IN_RETRY))) {
1537                 rbio = bch2_rbio_free(rbio);
1538                 bch2_rbio_done(rbio);
1539         }
1540         return;
1541 csum_err:
1542         /*
1543          * Checksum error: if the bio wasn't bounced, we may have been
1544          * reading into buffers owned by userspace (that userspace can
1545          * scribble over) - retry the read, bouncing it this time:
1546          */
1547         if (!rbio->bounce && (rbio->flags & BCH_READ_USER_MAPPED)) {
1548                 rbio->flags |= BCH_READ_MUST_BOUNCE;
1549                 bch2_rbio_error(rbio, READ_RETRY, BLK_STS_IOERR);
1550                 return;
1551         }
1552
1553         bch2_dev_io_error(ca,
1554                 "data checksum error, inode %llu offset %llu: expected %0llx:%0llx got %0llx:%0llx (type %u)",
1555                 rbio->pos.inode, (u64) rbio->bvec_iter.bi_sector,
1556                 rbio->pick.crc.csum.hi, rbio->pick.crc.csum.lo,
1557                 csum.hi, csum.lo, crc.csum_type);
1558         bch2_rbio_error(rbio, READ_RETRY_AVOID, BLK_STS_IOERR);
1559         return;
1560 decompression_err:
1561         __bcache_io_error(c, "decompression error, inode %llu offset %llu",
1562                           rbio->pos.inode,
1563                           (u64) rbio->bvec_iter.bi_sector);
1564         bch2_rbio_error(rbio, READ_ERR, BLK_STS_IOERR);
1565         return;
1566 }
1567
1568 static void bch2_read_endio(struct bio *bio)
1569 {
1570         struct bch_read_bio *rbio =
1571                 container_of(bio, struct bch_read_bio, bio);
1572         struct bch_fs *c        = rbio->c;
1573         struct bch_dev *ca      = bch_dev_bkey_exists(c, rbio->pick.ptr.dev);
1574         struct workqueue_struct *wq = NULL;
1575         enum rbio_context context = RBIO_CONTEXT_NULL;
1576
1577         if (rbio->have_ioref) {
1578                 bch2_latency_acct(ca, rbio->submit_time, READ);
1579                 percpu_ref_put(&ca->io_ref);
1580         }
1581
1582         if (!rbio->split)
1583                 rbio->bio.bi_end_io = rbio->end_io;
1584
1585         if (bch2_dev_io_err_on(bio->bi_status, ca, "data read")) {
1586                 bch2_rbio_error(rbio, READ_RETRY_AVOID, bio->bi_status);
1587                 return;
1588         }
1589
1590         if (rbio->pick.ptr.cached &&
1591             (((rbio->flags & BCH_READ_RETRY_IF_STALE) && race_fault()) ||
1592              ptr_stale(ca, &rbio->pick.ptr))) {
1593                 atomic_long_inc(&c->read_realloc_races);
1594
1595                 if (rbio->flags & BCH_READ_RETRY_IF_STALE)
1596                         bch2_rbio_error(rbio, READ_RETRY, BLK_STS_AGAIN);
1597                 else
1598                         bch2_rbio_error(rbio, READ_ERR, BLK_STS_AGAIN);
1599                 return;
1600         }
1601
1602         if (rbio->narrow_crcs ||
1603             rbio->pick.crc.compression_type ||
1604             bch2_csum_type_is_encryption(rbio->pick.crc.csum_type))
1605                 context = RBIO_CONTEXT_UNBOUND, wq = system_unbound_wq;
1606         else if (rbio->pick.crc.csum_type)
1607                 context = RBIO_CONTEXT_HIGHPRI, wq = system_highpri_wq;
1608
1609         bch2_rbio_punt(rbio, __bch2_read_endio, context, wq);
1610 }
1611
1612 int __bch2_read_extent(struct bch_fs *c, struct bch_read_bio *orig,
1613                        struct bvec_iter iter, struct bkey_s_c k,
1614                        struct bch_io_failures *failed, unsigned flags)
1615 {
1616         struct extent_ptr_decoded pick;
1617         struct bch_read_bio *rbio = NULL;
1618         struct bch_dev *ca;
1619         struct promote_op *promote = NULL;
1620         bool bounce = false, read_full = false, narrow_crcs = false;
1621         struct bpos pos = bkey_start_pos(k.k);
1622         int pick_ret;
1623
1624         pick_ret = bch2_bkey_pick_read_device(c, k, failed, &pick);
1625
1626         /* hole or reservation - just zero fill: */
1627         if (!pick_ret)
1628                 goto hole;
1629
1630         if (pick_ret < 0) {
1631                 __bcache_io_error(c, "no device to read from");
1632                 goto err;
1633         }
1634
1635         if (pick_ret > 0)
1636                 ca = bch_dev_bkey_exists(c, pick.ptr.dev);
1637
1638         if (flags & BCH_READ_NODECODE) {
1639                 /*
1640                  * can happen if we retry, and the extent we were going to read
1641                  * has been merged in the meantime:
1642                  */
1643                 if (pick.crc.compressed_size > orig->bio.bi_vcnt * PAGE_SECTORS)
1644                         goto hole;
1645
1646                 iter.bi_sector  = pos.offset;
1647                 iter.bi_size    = pick.crc.compressed_size << 9;
1648                 goto noclone;
1649         }
1650
1651         if (!(flags & BCH_READ_LAST_FRAGMENT) ||
1652             bio_flagged(&orig->bio, BIO_CHAIN))
1653                 flags |= BCH_READ_MUST_CLONE;
1654
1655         narrow_crcs = should_narrow_crcs(k, &pick, flags);
1656
1657         if (narrow_crcs && (flags & BCH_READ_USER_MAPPED))
1658                 flags |= BCH_READ_MUST_BOUNCE;
1659
1660         EBUG_ON(bkey_start_offset(k.k) > iter.bi_sector ||
1661                 k.k->p.offset < bvec_iter_end_sector(iter));
1662
1663         if (pick.crc.compression_type != BCH_COMPRESSION_NONE ||
1664             (pick.crc.csum_type != BCH_CSUM_NONE &&
1665              (bvec_iter_sectors(iter) != pick.crc.uncompressed_size ||
1666               (bch2_csum_type_is_encryption(pick.crc.csum_type) &&
1667                (flags & BCH_READ_USER_MAPPED)) ||
1668               (flags & BCH_READ_MUST_BOUNCE)))) {
1669                 read_full = true;
1670                 bounce = true;
1671         }
1672
1673         promote = promote_alloc(c, iter, k, &pick, orig->opts, flags,
1674                                 &rbio, &bounce, &read_full);
1675
1676         if (!read_full) {
1677                 EBUG_ON(pick.crc.compression_type);
1678                 EBUG_ON(pick.crc.csum_type &&
1679                         (bvec_iter_sectors(iter) != pick.crc.uncompressed_size ||
1680                          bvec_iter_sectors(iter) != pick.crc.live_size ||
1681                          pick.crc.offset ||
1682                          iter.bi_sector != pos.offset));
1683
1684                 pick.ptr.offset += pick.crc.offset +
1685                         (iter.bi_sector - pos.offset);
1686                 pick.crc.compressed_size        = bvec_iter_sectors(iter);
1687                 pick.crc.uncompressed_size      = bvec_iter_sectors(iter);
1688                 pick.crc.offset                 = 0;
1689                 pick.crc.live_size              = bvec_iter_sectors(iter);
1690                 pos.offset                      = iter.bi_sector;
1691         }
1692
1693         if (rbio) {
1694                 /* promote already allocated bounce rbio */
1695         } else if (bounce) {
1696                 unsigned sectors = pick.crc.compressed_size;
1697
1698                 rbio = rbio_init(bio_alloc_bioset(GFP_NOIO,
1699                                                   DIV_ROUND_UP(sectors, PAGE_SECTORS),
1700                                                   &c->bio_read_split),
1701                                  orig->opts);
1702
1703                 bch2_bio_alloc_pages_pool(c, &rbio->bio, sectors << 9);
1704                 rbio->bounce    = true;
1705                 rbio->split     = true;
1706         } else if (flags & BCH_READ_MUST_CLONE) {
1707                 /*
1708                  * Have to clone if there were any splits, due to error
1709                  * reporting issues (if a split errored, and retrying didn't
1710                  * work, when it reports the error to its parent (us) we don't
1711                  * know if the error was from our bio, and we should retry, or
1712                  * from the whole bio, in which case we don't want to retry and
1713                  * lose the error)
1714                  */
1715                 rbio = rbio_init(bio_clone_fast(&orig->bio, GFP_NOIO,
1716                                                 &c->bio_read_split),
1717                                  orig->opts);
1718                 rbio->bio.bi_iter = iter;
1719                 rbio->split     = true;
1720         } else {
1721 noclone:
1722                 rbio = orig;
1723                 rbio->bio.bi_iter = iter;
1724                 BUG_ON(bio_flagged(&rbio->bio, BIO_CHAIN));
1725         }
1726
1727         BUG_ON(bio_sectors(&rbio->bio) != pick.crc.compressed_size);
1728
1729         rbio->c                 = c;
1730         rbio->submit_time       = local_clock();
1731         if (rbio->split)
1732                 rbio->parent    = orig;
1733         else
1734                 rbio->end_io    = orig->bio.bi_end_io;
1735         rbio->bvec_iter         = iter;
1736         rbio->flags             = flags;
1737         rbio->have_ioref        = pick_ret > 0 && bch2_dev_get_ioref(ca, READ);
1738         rbio->narrow_crcs       = narrow_crcs;
1739         rbio->hole              = 0;
1740         rbio->retry             = 0;
1741         rbio->context           = 0;
1742         rbio->devs_have         = bch2_bkey_devs(k);
1743         rbio->pick              = pick;
1744         rbio->pos               = pos;
1745         rbio->version           = k.k->version;
1746         rbio->promote           = promote;
1747         INIT_WORK(&rbio->work, NULL);
1748
1749         rbio->bio.bi_opf        = orig->bio.bi_opf;
1750         rbio->bio.bi_iter.bi_sector = pick.ptr.offset;
1751         rbio->bio.bi_end_io     = bch2_read_endio;
1752
1753         if (rbio->bounce)
1754                 trace_read_bounce(&rbio->bio);
1755
1756         bch2_increment_clock(c, bio_sectors(&rbio->bio), READ);
1757
1758         percpu_down_read_preempt_disable(&c->mark_lock);
1759         bucket_io_clock_reset(c, ca, PTR_BUCKET_NR(ca, &pick.ptr), READ);
1760         percpu_up_read_preempt_enable(&c->mark_lock);
1761
1762         if (likely(!(flags & (BCH_READ_IN_RETRY|BCH_READ_LAST_FRAGMENT)))) {
1763                 bio_inc_remaining(&orig->bio);
1764                 trace_read_split(&orig->bio);
1765         }
1766
1767         if (!rbio->pick.idx) {
1768                 if (!rbio->have_ioref) {
1769                         __bcache_io_error(c, "no device to read from");
1770                         bch2_rbio_error(rbio, READ_RETRY_AVOID, BLK_STS_IOERR);
1771                         goto out;
1772                 }
1773
1774                 this_cpu_add(ca->io_done->sectors[READ][BCH_DATA_USER],
1775                              bio_sectors(&rbio->bio));
1776                 bio_set_dev(&rbio->bio, ca->disk_sb.bdev);
1777
1778                 if (likely(!(flags & BCH_READ_IN_RETRY)))
1779                         submit_bio(&rbio->bio);
1780                 else
1781                         submit_bio_wait(&rbio->bio);
1782         } else {
1783                 /* Attempting reconstruct read: */
1784                 if (bch2_ec_read_extent(c, rbio)) {
1785                         bch2_rbio_error(rbio, READ_RETRY_AVOID, BLK_STS_IOERR);
1786                         goto out;
1787                 }
1788
1789                 if (likely(!(flags & BCH_READ_IN_RETRY)))
1790                         bio_endio(&rbio->bio);
1791         }
1792 out:
1793         if (likely(!(flags & BCH_READ_IN_RETRY))) {
1794                 return 0;
1795         } else {
1796                 int ret;
1797
1798                 rbio->context = RBIO_CONTEXT_UNBOUND;
1799                 bch2_read_endio(&rbio->bio);
1800
1801                 ret = rbio->retry;
1802                 rbio = bch2_rbio_free(rbio);
1803
1804                 if (ret == READ_RETRY_AVOID) {
1805                         bch2_mark_io_failure(failed, &pick);
1806                         ret = READ_RETRY;
1807                 }
1808
1809                 return ret;
1810         }
1811
1812 err:
1813         if (flags & BCH_READ_IN_RETRY)
1814                 return READ_ERR;
1815
1816         orig->bio.bi_status = BLK_STS_IOERR;
1817         goto out_read_done;
1818
1819 hole:
1820         /*
1821          * won't normally happen in the BCH_READ_NODECODE
1822          * (bch2_move_extent()) path, but if we retry and the extent we wanted
1823          * to read no longer exists we have to signal that:
1824          */
1825         if (flags & BCH_READ_NODECODE)
1826                 orig->hole = true;
1827
1828         zero_fill_bio_iter(&orig->bio, iter);
1829 out_read_done:
1830         if (flags & BCH_READ_LAST_FRAGMENT)
1831                 bch2_rbio_done(orig);
1832         return 0;
1833 }
1834
1835 void bch2_read(struct bch_fs *c, struct bch_read_bio *rbio, u64 inode)
1836 {
1837         struct btree_iter iter;
1838         struct bkey_s_c k;
1839         unsigned flags = BCH_READ_RETRY_IF_STALE|
1840                 BCH_READ_MAY_PROMOTE|
1841                 BCH_READ_USER_MAPPED;
1842         int ret;
1843
1844         BUG_ON(rbio->_state);
1845         BUG_ON(flags & BCH_READ_NODECODE);
1846         BUG_ON(flags & BCH_READ_IN_RETRY);
1847
1848         rbio->c = c;
1849         rbio->start_time = local_clock();
1850
1851         for_each_btree_key(&iter, c, BTREE_ID_EXTENTS,
1852                            POS(inode, rbio->bio.bi_iter.bi_sector),
1853                            BTREE_ITER_SLOTS, k) {
1854                 BKEY_PADDED(k) tmp;
1855                 unsigned bytes;
1856
1857                 /*
1858                  * Unlock the iterator while the btree node's lock is still in
1859                  * cache, before doing the IO:
1860                  */
1861                 bkey_reassemble(&tmp.k, k);
1862                 k = bkey_i_to_s_c(&tmp.k);
1863                 bch2_btree_iter_unlock(&iter);
1864
1865                 bytes = min_t(unsigned, rbio->bio.bi_iter.bi_size,
1866                               (k.k->p.offset - rbio->bio.bi_iter.bi_sector) << 9);
1867                 swap(rbio->bio.bi_iter.bi_size, bytes);
1868
1869                 if (rbio->bio.bi_iter.bi_size == bytes)
1870                         flags |= BCH_READ_LAST_FRAGMENT;
1871
1872                 bch2_read_extent(c, rbio, k, flags);
1873
1874                 if (flags & BCH_READ_LAST_FRAGMENT)
1875                         return;
1876
1877                 swap(rbio->bio.bi_iter.bi_size, bytes);
1878                 bio_advance(&rbio->bio, bytes);
1879         }
1880
1881         /*
1882          * If we get here, it better have been because there was an error
1883          * reading a btree node
1884          */
1885         ret = bch2_btree_iter_unlock(&iter);
1886         BUG_ON(!ret);
1887         bcache_io_error(c, &rbio->bio, "btree IO error %i", ret);
1888         bch2_rbio_done(rbio);
1889 }
1890
1891 void bch2_fs_io_exit(struct bch_fs *c)
1892 {
1893         if (c->promote_table.tbl)
1894                 rhashtable_destroy(&c->promote_table);
1895         mempool_exit(&c->bio_bounce_pages);
1896         bioset_exit(&c->bio_write);
1897         bioset_exit(&c->bio_read_split);
1898         bioset_exit(&c->bio_read);
1899 }
1900
1901 int bch2_fs_io_init(struct bch_fs *c)
1902 {
1903         if (bioset_init(&c->bio_read, 1, offsetof(struct bch_read_bio, bio),
1904                         BIOSET_NEED_BVECS) ||
1905             bioset_init(&c->bio_read_split, 1, offsetof(struct bch_read_bio, bio),
1906                         BIOSET_NEED_BVECS) ||
1907             bioset_init(&c->bio_write, 1, offsetof(struct bch_write_bio, bio),
1908                         BIOSET_NEED_BVECS) ||
1909             mempool_init_page_pool(&c->bio_bounce_pages,
1910                                    max_t(unsigned,
1911                                          c->opts.btree_node_size,
1912                                          c->sb.encoded_extent_max) /
1913                                    PAGE_SECTORS, 0) ||
1914             rhashtable_init(&c->promote_table, &bch_promote_params))
1915                 return -ENOMEM;
1916
1917         return 0;
1918 }